Helicopters are generally designed so that the pilot controls roll and pitch with the right hand via a cyclic pitch stick, and the vertical axis with the left hand via a collective pitch control lever. Until now, helicopters and tilt-rotor aircraft with a side-by-side cockpit have used this configuration for the control members.
In a side-by-side cockpit with side sticks, this configuration raises a major problem in terms of the ergonomy for the (co)pilot in the left seat. The side stick installed to the right of the left seat prevents the pilot in the left seat from having easy access to the central console in order to act on the controls that are located thereon, such as an autopilot, and navigation and mission systems. In order to act on the central console, the pilot sitting on the left must use the right hand, and must therefore let go the side stick. The pilot thus temporarily looses piloting control in roll and pitch, unlike the (co)pilot on the right-hand side who keeps control with the right hand while using the left hand to act on the central console. In addition, when making this movement that requires passing an arm over the side stick, the pilot sitting in the left seat runs the risk of hitting the handgrip of the side stick and delivering untimely piloting orders that might be dangerous under certain circumstances, particularly when flying close to obstacles.
Proposals are made in French patent FR-2 479 133 for a fly-by-wire (FBW) control system for a helicopter that has four control axes (pitch, roll, yaw, lift); the system has a force control lever that is sensitive relative to three or four control axes; the signals delivered by each force sensor are processed in a manner that includes applying both a “dead band”, and proportional and integral (PI) amplification.
French patent FR-2 576 281 describes an aircraft cockpit provided with a side stick, and a seat in which an armrest is hinged.
French patent FR-2 578 221 describes a mechanical system for coupling together two side sticks for piloting an aircraft.
U.S. Pat. No. 5,137,234 describes another device for mechanically coupling side sticks together.
French patent FR-2 754 515 describes a tactile warning system in the event of multiple/simultaneous piloting by two pilots using two mechanically independent control sticks.
In spite of the theoretical advantages of those devices, there remains a major need for rotorcraft flying controls that are more ergonomic.